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this presentaion is free for every medical student by the end of this presentation you will be able to identify cerebral strokes and determine the age of the pathology good luck .. Dr Thamir alotaify
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Brain hemorrhage Vs infarction in CT and MRI
Thamir Diab Alotaify4th year – medical student
NBU – medical college
Objectives
• Types of cerebral strokes and etiology• CT and MRI in cerebral hemorrhage • CT and MRI in cerebral infarction • 4-min Vedio for learning purpose• Conclusion
Intracrainial hemorrhage
Def / active bleeding inside the cranial cavity Types :- Epideural - Subdeural - Subarachnoid - Intracerebral (intraparnchymal)- Intraventricular
Etiology
• Generally most common cause of ICHs are traumatic causes
• And the most common cause of such traumas are RTAs
• Always it is nessery to evaluate the head and neck after RTAs
Clinically +++ radiologically Even if the patient is Asymptomaic(lucid interval )
CT and MRI in ICH • CT scan is the modality of choice in traumatic head
injuries ( in ER)• Why ? - Rapid - It can shows the bone status - It can detect the early onset of hemorrhge • So the CT good for 3 Bs -Blood -Brain -Bone
Stages of brain hemorrhage in CT
• Acute : hyperdense • Sub acute : isodense • Chronic : hypodense
CT appearance of hemorrhage. Serial CT scansof right thalamic hematoma. (A) Acute ICH in theright thalamus with mean attenuation 65 HU. (B) CTperformed 8 days later than (A); the periphery ofthe hematoma is now isodense to the brain whilethe center of the hematoma has mean attenuation45 HU. (C) CT performed 13 days later than (A) showscontinued evolution of the hematoma with decreasingattenuation. (D) CT performed 5 months laterthan (A) shows a small area of encephalomalacia in
ICH in MRI
• MRI is not a best choice for urgent diagnosis , it takes time and may be not available , and not good for bone status (not usefull in acute head injury )
• But it is the best modality for brain paranchymal assessment ( infarcts, demyelinatind dis , Tumors )
Brain infarction • Def/ necrosis of brain tissue due to many causes• types : (global , focal)• Most common cause : ischemia• Other causes : - Metabolic : hypoglycemia - Toxic : drugs • Cerebral infarction it can be detected in both CT & MRI • CT may appear normal in hyperacute state ( <3h)• MRI can detect small infarction at the moment
Cerebral infarction on CT• Hyperacute : before 3houres of onset ..normal• Early acute (4-6) :- Dense MCA sign - Obscuration of the lenticular nucleus - insular ribbon Sign• Late acute : - Low density basalganglia- sulcal effacement• Subacute :- Increasing mass effect- Wedge-shaped low density area involving gray and white matter- Possible hemorrhagic transformation
Chronic : (>3days)
-Well demarcated hypodensity Simillar density to CSF--ve mass effect (pulled midline)-Dilataion of ventricles (Encephalomalacia )
Early acute (3-6 )
MCA sign
Subacute cerebral infarction
Marked ill defined hypodense area involving most of the RT cerebral hemisphere and shifting the midline
Chronic cerebral infarction
Massive Hypodense area in LT cerebral hemispherSimillar density of CSF + ipsilateral widening of lateral ventricle
Cerebral infarction in MRI +ve DWI
Imaging Findings of Stroke:
• MR imaging of the brain is far more sensitive than CT imaging to recognize acute infarction.
• Diffusion wtd. pulse sequence (DW imaging) is the most sensitive MR sequence to demonstrate stroke. This sequence is sensitive to restricted diffusion within the cell from stroke-induced cytotoxic edema and the region of acute stroke is seen as an area of bright signal on DWI Cytotoxic edema can occur immediately after the initial insult thus DWI images can reveal, the area of acute infarct immediately after the insult.
• Intravascular contrast enhancement, another sign of early stroke (Figure 1f).
• Sulcal effacement, gyral edema (Fig. 5b), loss of gray-white matter interface can occur within 12 hours of stroke.
• Parenchymal contrast enhancement (Fig. 6d), mass effect (Fig. 4b) and hemorrhage can occur within 1-7 days of insult.
Subacute infarct: (1 week to 8 weeks)
•Focal area of encephalomalacia•Porencephalic dilatation of adjacent ventricle.• Residual old blood products may be present.
Old Infarct:
• Contrast enhancement slowly decreases in time but can persist for 8 weeks, with decreasing mass effect and abnormal signal intensity:
Acute Stroke (up to 7 days)
conclusion
• There are sequence of events in cerebral strokes :
- Hyperacute- Acute - Subacute - Chronic • CT is best for hemorrhagic • MRI is best to detect the ischemic at the onset